Lifting device

ABSTRACT

A lifting device for attachment to a three-point tractor lift mechanism which has a mast supported and elevated by two links. A flexible member is attached to a link connected to the mast such that elevation of the mast causes elevation of a carriage movably guided by the mast.

[111 3,826,392 [4 1 July 30, 1974 United States Patent [191 Farley 12/1970 Russell.....

[ LIFTING DEVICE [76] Inventor:

Brian Farley, 9 Struben Rd., Claremont, South Africa May 1, 1973 Primary Examiner--Robert G. Sheridan Assistant Examiner-Lawrence J. Oresky Attorney, Agent [22] Filed:

, 0r Firm-Larson, Taylor &Hinds [21] Appl. No.: 356,190

ABSTRACT [52] US. Cl....... 214/672, 214/146.5, 214/766 3,366,260 1/1968 Salna et a1. 214/671 12 Claims, 11 Drawing Figures PATENTED M3 sum 10F e Pmmmmamau saw an: s

LIFTING DEVICE The present invention relates to lifting devices.

More particularly the invention relates to lifting devices for attachment to a three-point tractor liftmechanism.

It is an object of the invention to provide a simple lifting device which easily may be connected to and dis connected from a three-point tractor lift mechanism.

According to the invention, a lifting device for attachment to a three-point tractor lift-mechanism includes I a. a lifting member;

b. a mast;

c. mast attachment means for attaching the mast at its lower end to a pair of lifting arms of a tractor;

d. movable-means for movably mounting the lifting member on the mast;

e. a connection arm pivotably attached to the mast and adapted for pivotable attachment to a tractors body;

f. fixed guide means attached to the upper end of the mast;

g. a floating guide means;

h. a flexible member attached at one end to the lifting a member, extending over the fixed guide means and the floating guide means and attached at its other end to the mast;

i. a joining-member joining the floating guide means to the connection arm and being connected to the latter in an intermediate position between its connecting ends;

wherein operation of the tractor lifting arms is adapted to cause the mast to be lifted with simultaneous pivotation of the connection arm, which in turn by by means of the joining member pulls the floating guide means away from the fixed guide means, whereby the flexible element pulls the lifting member to move along the mast.

Thelifting member may include a frame and a pair of fork arms extending rearwardly away from the frame. The pair of fork arms, may be pivotably connected to the frame and may be adapted to pivot from a position adjacent the frame to a position extending substantially perpendicularly away from the frame. Releasable arm locking means may be provided on the frame for locking the arms in position adjacent the frame.

The mast may include a frame.

The mast attachment means may include a pair of blocks having outwardly directed pins for insertion into eyes of lifting arms of a tractor. The pair of blocks also may have pins of a different diameter directed inwardly and may be removably attached to the mast for providing either pin directed outwardly depending on the diameter of eyes of the lifting arms of a tractor to which the mast is to be fitted.

The mast may include two spaced channel section members, which are substantially parallel.

The channel members may face with their open sides towards each other. The channel members may have elongated shoulders on their open sides, the shoulders of one channel member facing each other.

The movable means may include two pairs of rollers mounted by way of connection arms to the lifting mempie with reference to the ber, each pair of rollers engaging in one channel member.

A lower stop member may be provided at the lower end of the mast for prevention of withdrawal of the 1ifting member from this end. Also an upper stop member may be provided at the upper end of the mast for prevention of withdrawal of the lifting member from that end.

The fixed guide means may be a pulley rotatably mounted to the mast at its upper end.

The floating guide means may be a pulley rotatably mounted in a U-shaped carrier.

The flexible member may be acable.

The connection arm and'the joining member may be adjustable in length.

The invention will now be described by way of examaccompanying schematic drawings.

In the drawings,

FIG. 1 shows a side view of a-lifting device in accordance with the invention, and as in its lower position;

FIG. 2 shows a rear view of the device seen along arrow II in FIG. 1 (but with some tractor connection members etc. omitted for the sake of clarity);

- FIG. 3 shows a sectional side view of the device seen along arrows IIIIII in FIG. 2;

FIG. 4 shows, on a larger scale, a side view of the mast attachment block seen along arrow IV in 16. 1;

FIG. 5 shows, on a larger scale, a side view of the lower stop member seen along arrow V in FIG. 2;

FIG. 6 shows, on a larger scale, a sectional view of the cross-section of the mast channel'frame seen along arrows VIVI in FIG. 3;

FIG. 7 shows the same side view as in FIG. I but now in its upper lifting position;

FIG. 8 shows, on a larger scale, a perspective view of the fixed guide pulley and the floating pulley;-

FIG. 9 shows, on a larger scale, a side view of the connection of the connection arm to the mast;

FIG. 10 shows, on a smaller scale and in simplified form the lifting device as connected to a tractor and being in the lower position; and

FIG. 11 shows the same view as FIG. 10 but with the lifting device in its upper position.

Referring to FIGS. 1 and 2 the lifting device, generally indicated by reference numeral 20 includes the following basic parts:

1. A lifting member 22.

2. A mast 24.

3. Mast attachment means 26 for attaching the mast to the lifting arms of a tractor.

4. Movable means v28 for removably connecting the lifting member 22 to-the mast 24.

5. A connection arm 30 for connecting the mast 24 to a tractor body.

6. A fixed guide means in the form of a pulley 32.

7. A floating guide means in the form of a pulley 34.

8. A joining member 36 joining the pulley 34 to the connection arm 30.

9. A lifting cable 38.

The lifting member 22 includes a frame 40 with sides 40.1 and transverse beams 40.2. A pair of fork arms 42, 44 are pivotably connected to the frame by means of plates and pins 46, 48 respectively. These arms 42,44

' may be lifted vertically to rest against the frame 40 (as shown by dotted lines 42.1 in FIG. 1) and can be held in this position by means of locking hooks 50,52,which are pivotably connected to the sides 40.1 of the frame The mast 24 includes two vertical spaced channel guides 54,56. The cross-section of these channel guides is shown in FIG. 6. (The guides have facing shoulders, e.g. 56.1 in FIG. 6). The channel guides 54,56 are joined .by transverse members, which include ;a top channel beam 58 (which also serves as upper stop member), an intermediate beam 60 and a lower beam 62.

The mast attachment means 26 includes two similar blocks 64,66. One of the blocks (i.e. 64) is illustrated in FIG. 4. (Although only this block 64 is described the same applies to block 66 mutadis mutandis.) The block 64 includes two rods 68,70 welded together. The rods 68,70 respectively have pins 72,74 at their ends. These pins 72,74 are of different diameter to fit different eye diameters of the lifting linkage arms of a tractor. The block 64 is attachable to the beam 62 by fitting into an open channel housing 76 welded to the beam 62. A bolt 78 passes through the channel housing 76 and a hole in the block 64 for attachment. It will be notedthat the hole for the bolt 78 is closer to the pin 72 than to the pin 74. This provides that, when reversing the block 64, the pin 74 will project further to the left as compared to the pin 72 as illustrated. Accordingly the distance between these pins 74 (i.e. when both blocks 64,66 are reversed) is greater to provide forthe greater distance between the tractor linkage arms having eyes with di-' ameters fitting such diameter pins.

The movable means 28 is illustrated in more detail in FIGS; 3 and 6. It consists of two pairs of arms 80,82 connected .to the frame 40. Each of these arms carry a roller 84 or 86, as the case may be, engaging in rolling fashion in the channel guides 54,56. Thus there are four rollers, two on each horizontal level. The connection arm 30 (see FIG. 1 includes a threaded bolt 88 engaging in a threaded cylinder 90 which is connected to a stirrup plate 92 pivotably carrying a connection block 94. The connection block 94 has two holes 96, 98 of different diameter to cater for different diameter connection bolts of tractors. The connection arm 30 further includes an adjustment beam 100 which is connected at one end to the cylinder 90 by means of a collar 102. The collar 102 slides on the cylinder 90. Referring now to FIG. 9, the free end of the rod 88 terminates into a stirrup 104. In the stirrup 104 a connection block 106 is provided, and the stirrup 104, the block 106 and the free end of the beam 100 are joined together by-means of a bolt 108. The block 106 is pivotably connected to two spaced vertical adjustment beams 110,112, which are connected between the transverse beams 60 and 62 (see FIG. 2).

The pulley 32is mounted between two plates 114, 116'which are connected to the beam 58 (see FIG. 8).

The floating pulley 34 is rotatably mounted in a stirrup 118.

The joining member 36 includes a threaded rod 120, connected to the stirrup 118, and being screw connected to a cylinder 122. The cylinder 122 is in turn pivotably connected via a pair of plates 124 to the beam 100 (FIG. 1).

The cable 38 is connected at one end to a'pin'126 fitted between two plates 128 which are fixed to the frame 40 (FIG. 2). From here the cable 38 extends over the fixed pulley 32 and passes over the floating pulley 34, to be connected at its other end to a pin 130 mounted between the plates 114,116 (see FIG. 8).

FIG. 5 illustrates the lower stop 132. It includes an L-shaped member 134 pivotably mounted between the beams 110,112 by means of a pin 136. The member 134 is adapted to engage the lower transverse beam 40.2 ofthe frame 40, should it drop down.

The operation of the device 20 will now be described. Reference will be made to the various drawings, in particular FIGS. 1, 2, 7, .10 and 11.

Before use, the device 20 is connected to the three point lifting system of a tractor 136. This system includes a pair of lifting arms 138,140, pivotably attached to the tractorand adapted to be lifted, and a fixed pivot point 142 on the tractor body. FIGS. 1 and 10 show the normal position in which the tractor 136 is free to move about.

The tractor 136 is operated to move the arms 42, 44 to pass below a load to be lifted. By operating the tractors lifting mechanism, the arms 138,140 are moved to the position as illustrated in FIGS. 7 and 11. Thereby the mast 24 has been lifted, and simultaneously the frame 40 also has been raised higher in relation to the mast 24. This is caused in that the connection arm 30, which is moved upwardly, lifts the joining arm 36 up only for a very short distance. Thereby the pulley 34 is pulled away from the mast 24 and with it the cable 38 is pulled out. The cable 38 pulls the frame 40 up to slide along the channel guides 54, 56.

The operation of the cable 38 may be excluded by disconnecting the plate 124 from the beam 100. The frame 40 then will merely rest on the lower stop 134 and will be moved for the same distance as the mast 24.

The slackness in the cable 32 can be taken up by varying the length of the joining arm 36 by suitable rotation of the cylinder 122.

In the FIGS. 1, 7, l0 and 11 the mast 24 and the frame 40 are shown to be substantially vertical. To obtain an inclination, the connection of the connection arm 30 to the beam 112 must be varied (see FIG. 9). For tilting towards the tractor, the connection is moved upwardly. For tilting away from the tractor, it is lowered. By turning the cylinder the length of the arm 30 may be varied. This may be necessary for different types of tractors.

The distance through which the frame 40 (and thus the forks 42,44) are lifted may also be varied. FIGS. 7 and 11 show the maximum lifting height. The variation is done by adjusting the connection of the plates 124 on the beam 100. By moving the connection towards the mast 24, the lifting distance is decreased. The higher the lift, the lower the possible load. In other words, when selecting a shorter lift, a greater load may be lifted.

I claim:

1. A lifting device for attachment to a three-point tractor lift mechanism which includes a. a lifting member;

b. a mast;

c. mast attachment means for attaching the mast at its lower end to a pair of lifting arms of a tractor;

d. movable means for movably mounting the lifting member on the mast;

e. a connection arm pivotably attached to the mast and adapted for pivotable attachment to a tractors body;

f. fixed guide means attached to the upper end of the mast;

g. a floating guide means;

h. a flexible member attached at one end to the lifting member, extending over the fixed guide means and the floating guide means and attached at its other end to the mast;

i. a joining member joining the floating guide means to the connection arm and being connected to the latter in an intermediate position between its connecting ends;

wherein operation of the tractor lifting arms is adapted to cause the mast to be lifted with simultaneous pivotation of the connection arm, which in turn by means of the joining member pulls the floating guide means away from the fixed guide means, whereby the flexible member pulls the lifting member to move along the mast.

2. A lifting device as claimed in claim 1, in which the lifting member includes a frame and a pair of fork arms extending rearwardly away from the frame, the pair of fork arms being pivotably connected to the frame, and being adapted to pivot from a position adjacent the frame to a position extending substantially perpendicularly away from the frame.

3. A lifting device as claimed in claim 2, in which releasable arm locking means are provided on the frame for locking the arms in position adjacent the frame.

4. A lifting device as claimed in claim 1, in which the mast includes a frame having two spaced channel section members, which are substantially parallel.

5. A lifting device as claimed in claim 1, in which the mast attachment means includes a pair of blocks having outwardly directed pins for insertion into eyes of lifting arms of a tractor and also pins of a different diameter directed inwardly, the blocks being removably attached to the mast for providing either pin directedoutwardly depending on the diameter of eyes of the lifting arms of a tractor to which the mast is to be fitted.

6. A lifting device as claimed in claim 4, in which the channel members face with their open sides towards each other. Y

7. A lifting device as claimed in claim 6, in which the channel members have elongated shoulders on their open sides, the shoulders of one channel member facing each other, and in which the movable means includes two pairs of rollers mounted by way of connection arms to the lifting member, each pair of rollers engaging in one channel member.

8. A lifting device as claimed in claim 1, in which a lower stop member is provided at the lower end of the mast for prevention of withdrawal of the lifting member from this end, and an upper stop member is provided at the upper end of the mast for prevention of withdrawal of the lifting member from this end.

9. A lifting device as claimed in claim 1, in which the fixed guide means is a pulley rotatably mounted to the mast at its upper end and the floating guide means is a pulley rotatably mounted in a U-shaped carrier.

' 10. A lifting device as claimedin claim 1, in which the flexible member is a cable.

11. A lifting device as claimed in claim 1, in which the connection arm is adjustable in length, and is adjustably connected to the mast.

12. A lifting device as claimed in claim 1, in which the joining member is adjustable in length, and is ad justably connected to the connection arm. 

1. A lifting device for attachment to a three-point tractor lift - mechanism which includes a. a lifting member; b. a mast; c. mast attachment means for attaching the mast at its lower end to a pair of lifting arms of a tractor; d. movable means for movably mounting the lifting member on the mast; e. a connection arm pivotably attached to the mast and adapted for pivotable attachment to a tractor''s body; f. fixed guide means attached to the upper end of the mast; g. a floating guide means; h. a flexible member attached at one end to the lifting member, extending over the fixed guide means and the floating guide means and attached at its other end to the mast; i. a joining member joining the floating guide means to the connection arm and being connected to the latter in an intermediate position between its connecting ends; wherein operation of the tractor lifting arms is adapted to cause the mast to be lifted with simultaneous pivotation of the connection arm, which in turn by means of the joining member pulls the floating guide means away from the fixed guide means, whereby the flexible member pulls the lifting member to move along the mast.
 2. A lifting device as claimed in claim 1, in which the lifting member includes a frame and a pair of fork arms extending rearwardly away from the frame, the pair of fork arms being pivotably connected to the frame, and being adapted to pivot from a position adjacent the frame to a position extending substantially perpendicularly away from the frame.
 3. A lifting device as claimed in claim 2, in which releasable arm locking means are provided on the frame for locking the arms in position adjacent the frame.
 4. A lifting device as claimed in claim 1, in which the mast includes a frame having two spaced channel section members, which are substantially parallel.
 5. A lifting device as claimed in claim 1, in which the mast attachment means includes a pair of blocks having outwardly directed pins for insertion into eyes of lifting arms of a tractor and also pins of a different diameter directed inwardly, the blocks being removably attached to the mast for providing either pin directed outwardly depending on the diameter of eyes of the lifting arms of a tractor to which the mast is to be fitted.
 6. A lifting device as claimed in claim 4, in which the channel members face with their open sides towards each other.
 7. A lifting device as claimed in claim 6, in which the channel members have elongated shoulders on their open sides, the shoulders of one channel member facing each other, and in which the movable means includes two pairs of rollers mounted by way of connection arms to the lifting member, each pair of rollers engaging in one channel member.
 8. A lifting device as claimed in claim 1, in which a lower stop member is provided at the lower end of the mast for prevention of withdrawal of the lifting member from this end, and an upper stop member is provided at the upper end of the mast for prevention of withdrawal of the lifting member from this end.
 9. A lifting device as claimed in claim 1, in which the fixEd guide means is a pulley rotatably mounted to the mast at its upper end and the floating guide means is a pulley rotatably mounted in a U-shaped carrier.
 10. A lifting device as claimed in claim 1, in which the flexible member is a cable.
 11. A lifting device as claimed in claim 1, in which the connection arm is adjustable in length, and is adjustably connected to the mast.
 12. A lifting device as claimed in claim 1, in which the joining member is adjustable in length, and is adjustably connected to the connection arm. 